Using Pulse Width Modulation (PWM) interface in kernel module

Question

I'm new in kernel development driver and I'm trying to develop a Linux kernel module, using the this module information:

http://lxr.free-electrons.com/source/drivers/pwm/pwm-tiehrpwm.c

But I didn't understand how to use it. How could adapt this module or better, how to create a new module using functions contained in this file like ehrpwm_pwm_config, ehrpwm_pwm_enable?

PS:I don't want to use sysfs, I would configure the pwm signal programmatically. I'm using a Beaglebone Black board running a Debian distribution , and cape-universaln.

Thanks

Answer 1

You need to enable CONFIG_PWM_TIEHRPWM in your .config file of your linux-kernel. By default, CONFIG_PWM_TIEHRPWM is not set and you need to enable it as CONFIG_PWM_TIEHRPWM=y , if you want to build it as a part of kernel image, or as CONFIG_PWM_TIEHRPWM=m , if you want to build it as a LKM .

Then, build your kernel as make -j12 and insmod your module as:

#insmod /lib/modules/$uname -r/drivers/pwm/pwm_tiehrpwm.ko if you have built it as a LKM . Check Linux kernel documentation on how to configure pwm !